United States Army Corps of Engineers (USACE) Dr. Marion Divers presented updates on the Chautauqua Lake Aquatic Ecosystem Restoration Project at a USACE Pittsburgh District virtual community meeting on Wednesday from 6 to 8 p.m.

PITTSBURGH–By now, the U.S. Army Corps of Engineers has a good idea of the issue facing Chautauqua Lake. Now, everyone’s waiting to see potential recommended solutions.

The United States Army Corps of Engineers took to the internet to address several issues surrounding Chautauqua Lake and provide updates on the Corps Chautauqua Lake Aquatic Ecosystem Restoration Project on Wednesday. Dr. Marion Divers presented information and spoke about several topics relating to the corps’ restoration efforts and approaches taken to help revitalize the lake’s natural resources.

Marine ecosystem degradation threatens Chautauqua Lake’s sustainability via three interrelated pathways: sedimentation, growth of nuisance aquatic vegetation, and harmful algal blooms (HABs) – .lrd.usace.army.mil.

Divers said excess sedimentation within the lake degrades the quality and availability of critical habitats, impacts navigation and recreation, and increases flood risk. They also noted that nuisance vegetation accumulated sediments promote the growth of nuisance and invasive aquatic plant species, such as Eurasian watermilfoil, which have dramatically impacted this ecosystem and degraded recreational opportunities.

Harmful algal blooms, sediment, and nutrient inputs can also contribute to increased HAB frequency and nutrients within the lake. More than 500 documented HABs have been recorded since 2012, with 61 HAB notices issued in 2022 alone. HABs affect human health risks due to recreation exposure, impact drinking water quality, and result in lost economic revenue. She said that increasing intense and frequent significant rain events and associated erosion and sedimentation rates further degrade habit quality and availability within the lake.

Divers said Ecosystem Restoration is one of the primary missions of the USACE. The purpose of the AER mission is to restore degraded ecosystem structure, function, and dynamic processes.

Additionally, utilizing the USACE planning process, the Corps will compare alternative plans, evaluate costs and benefits, and recommend a specific course of action to Congress (the Chief’s Report) to support the restoration of Chautauqua Lake’s aquatic ecosystem. ​Congress may then authorize and fund the identified course of action for construction. This project began in September 2024 and is expected to take about three years.

Drivers highlighted some of the public input USACE revived from the public comment charettes held by the Army Corps of Engineers in January.

She noted public concerns about sedimentation caused by shoreline and streambank erosion caused by land development and agricultural practices along the lake’s shoreline and the watershed. That sedimentation has impacted the lake’s quality and availability of aquatic and deep-water habitats.

A formal timeline study consists of scoping, which includes a feasibility cost share agreement; identifying the federal interest in the project and the initial array of alternatives; presenting the plan up the vertical chain-of-command; drafting a report and releasing it for public review; endorsing a tentatively selected course of action; the district engineer recommendation, the final submitted plan for review; and a Washington-Level Review – the chief’s report, in which the Chief of the Army Coypr of Engineers presents a recommended course of action to Congress for authorization.

Another course of action Divers spoke about could be a ‘No Action Plan or a Future Without a Project. .

“I told you all that we also identified the FWOP, or future without a project,” Divers said. “What happens if we don’t do anything? We think about this carefully. We consider this outcome so that we have a baseline to compare our plan to. This is important.”

With a No Action Plan or FWOP, it is believed the following could occur: continued streambank and shoreline erosion due to agricultural and increased residential development; increased runoff and sedimentation – continued nutrient issues; decreased species diversity and abundance; further loss of habitat and ecosystem function degradation due to HABs and nutrients; increased sediment could cause the lake’s capacity to change; Hydrology will be influenced by climate trends, such as higher water temperatures, changing precipitation patterns and less ice cover; increased cover of invasive species’ HABs could create issues with drinking water and recreation use of the lake; and economic impacts from the loss of recreational dollars from rentals, gas, food and has implications to the local economy,” she said.